Lung volume recruitment in multiple sclerosis

Abstract

Introduction: Pulmonary function abnormalities have been described in multiple sclerosis including reductions in forced vital capacity (FVC) and cough but the time course of this impairment is unknown. Peak cough flow (PCF) is an important parameter for patients with respiratory muscle weakness and a reduced PCF has a direct impact on airway clearance and may therefore increase the risk of respiratory tract infections. Lung volume recruitment is a technique that improves PCF by inflating the lungs to their maximal insufflation capacity.

Objectives: Our goals were to describe the rate of decline of pulmonary function and PCF in patients with multiple sclerosis and describe the use of lung volume recruitment in this population.

Methods: We reviewed all patients with multiple sclerosis referred to a respiratory neuromuscular rehabilitation clinic from February 1999 until December 2010. Lung volume recruitment was attempted in patients with FVC <80% predicted. Regular twice daily lung volume recruitment was prescribed if it resulted in a significant improvement in the laboratory.

Results: There were 79 patients included, 35 of whom were seen more than once. A baseline FVC <80% predicted was present in 82% of patients and 80% of patients had a PCF insufficient for airway clearance. There was a significant decline in FVC (122.6 mL/y, 95% CI 54.9-190.3) and PCF (192 mL/s/y, 95% 72-311) over a median follow-up time of 13.4 months. Lung volume recruitment was associated with a slower decline in FVC (p<0.0001) and PCF (p = 0.042).

Conclusion: Pulmonary function and cough decline significantly over time in selected patients with multiple sclerosis and lung volume recruitment is associated with a slower rate of decline in lung function and peak cough flow. Given design limitations, additional studies are needed to assess the role of lung volume recruitment in patients with multiple sclerosis.

Conflict of interest statement

Competing Interests: The authors have declared that no competing interests exist.

Figures

Figure 1. Comparative time course of average FVC, MIC, PCF and PCFLVR.

Only observations where all variables were present were included. FVC, PCF and PCFLVR declined significantly at an average rate of 89.9 mL/y, 154 mL/s/y and 89.1 mL/s/y respectively. The MIC did not decline significantly with an average rate of decline of 50.6 mL/y.